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| Spread of light from beauty dish https://www.paulcbuff-techforum.com/viewtopic.php?f=8&t=3806 |
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| Author: | stmpqwn [ Sun Nov 25, 2012 2:50 am ] |
| Post subject: | Spread of light from beauty dish |
I'm trying to better understand limitations - or no limitations - using a 22" beauty dish and AB 1600 when photographing groups (outdoors). (I have 2 of each.) Can anyone help me understand the spread of light from the beauty dish and AB1600? At what point do I make a determination to bring in a 2nd light and dish/umbrella. I'm seeking even coverage for small groups 3-7 subjects as well as large groups 8 - 40 or 50. When using a beauty dish, what must I know in order to get even coverage of my group, side to side and front to back. I'd like to understand the spread of one light/22" dish and how distances from light to subject affect the coverage of group or subjects. Do I understand right that the light blocker is best saved for using when the distance from the light to subject is less that 7 feet? Under what circumstances would I want to add the diffusion sock? Can I plug 2 AB 1600's into one Mini Vagabond and have fairly quick recycle time at 1/2 power or less on each firing at the same time? I appreciate any experience on what has worked or not or other information that will help. Thanks! Laurie |
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| Author: | Technical Support [ Sun Nov 25, 2012 11:09 am ] |
| Post subject: | Re: Spread of light from beauty dish |
Silver or white beauty dish? |
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| Author: | stmpqwn [ Sun Nov 25, 2012 1:52 pm ] |
| Post subject: | Re: Spread of light from beauty dish |
Technical Support wrote: Silver or white beauty dish? I have both. |
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| Author: | Technical Support [ Mon Nov 26, 2012 11:29 am ] |
| Post subject: | Re: Spread of light from beauty dish |
The silver beauty dish will have a beam spread of 45 degrees. The white will have a spread of 130 degrees. Beam spread is defined as the angle from the center to -1f on either side (so if -1f is 10 degrees from center, there is a 20 degree beam spread since it spreads 10 degrees in the opposite direction). However, what a "beam spread" spec does not tell you is how much feathering happens past that mark. You could have a very sharp fall off, or very feathered fall off. The white beauty dish, as with any white modifier, will have a very diffused fall off past the -1f mark. The silver beauty dish will have a sharper fall off. Once you add the sock to the silver dish, the relative power and spread will be similar to that of a white beauty dish. It is also important to know that subjects closer to a light source will be brighter than those farther away. The farther away the light source, the more the discrepancy evens out. For large groups, a popular method is to light the left side with the right light, and the right side with the left light. Or, with one light, aim the light at or past the opposite end. The most intense light will go that direction, and letting the lower intensity light fall on the closer subjects. I don't know that using the light blocker will hurt beyond 7 feet, but it loses its effectiveness, as the entire reflector becomes a point source of light. The diffusion sock will soften specular highlights when at close ranges. Farther away, the dish becomes a point source, and more prone to become a specular highlight. 2 B1600's at half power will recycle in about 3 seconds. |
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